Conveyor oven

ABSTRACT

An accelerated cooking or speed cooking conveyor oven with at least one discrete cooking zone. The oven includes a first and a second gas directing member configured to cause the gas from the first gas directing member to collide with the gas fron the second gas directing member upon the upper or lower surface of the food product being conveyed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. ProvisionalApplication No. 60/550,578, filed Mar. 5, 2004, entitled “SPEED COOKINGCONVEYOR OVEN”; the benefit of U.S. Provisional Application No.60/551,268,filed Mar. 8, 2004, entitled “ANTENNA COVER; and the benefitof U.S. Provisional Application No. 60/615,888, filed Oct. 5, 2004,entitled “CATALYST FOR SPEED COOKING OVEN”.

The present application is a continuation-in-part of U.S. applicationSer. No. 10/614,479, filed Jul. 7, 2003, entitled “SPEED COOKING OVEN”,currently pending, which claims the benefit of U.S. ProvisionalApplication No. 60/394,216, entitled “RAPID COOKING OVEN”, filed Jul. 5,2002; a continuation-in-part of U.S. application Ser. No.10/614,268,filed Jul. 7, 2003, entitled “MULTI RACK SPEED COOKING OVEN”,currently pending, which claims the benefit of U.S. ProvisionalApplication No. 60/394,216, entitled “RAPID COOKING OVEN”, filed Jul. 5,2002; a continuation-in-part of U.S. application Ser. No. 10/614,710,filed Jul. 7, 2003, entitled “SPEED COOKING OVEN WITH GAS FLOW CONTROL”,currently pending, which claims the benefit of U.S. ProvisionalApplication No. 60/394,216, entitled “RAPID COOKING OVEN”, filed Jul. 5,2002; a continuation-in-part of U.S. application Ser. No. 10/614,532,filed Jul. 7, 2003, entitled “SPEED COOKING OVEN”, currently pending,which claims the benefit of U.S. Provisional Application No. 60/394,216,entitled “RAPID COOKING OVEN”, filed Jul. 5, 2002.

The present application contains technical disclosure in common withPCT/US03/021225, entitled “SPEED COOKING OVEN” filed Jul. 5, 2003,currently pending, which claims the benefit of U.S. ProvisionalApplication No. 60/394,216, entitled “RAPID COOKING OVEN”, filed Jul. 5,2002; and contains technical disclosure in common with PCT/US04/035252entitled “SPEED COOKING OVEN WITH SLOTTED MICROWAVE ANTENNA”, filed Oct.21, 2004, which claims the benefit of U.S. Provisional Application No.60/513,110, filed Oct. 21, 2003,entitled “SLOTTED ANTENNA”, which alsoclaims the benefit of U.S. Provisional Application No. 60/513,111, filedOct. 23, 2003, entitled “MICROWAVE ANTENNA COVER FOR RAPID COOKINGOVEN”, which also claims the benefit of U.S. Application No. 60/614,877,filed Sep. 30, 2004, entitled “SLOT ANTENNA”. Each of these applicationsare incorporated herein by reference as if fully set forth.

BACKGROUND

The typical cook time for a food product such as a fresh medium sizepizza (12 to 14 inch) through a conventional conveyor oven isapproximately 7 minutes, and 15 minutes through a deck style oven. Theconveyor oven reduces cooking time as compared to the deck oven and alsosimplifies the cooking procedure because the food product isautomatically loaded into and unloaded from the cooking tunnel.

Conveyor ovens typically utilize a continuous open link conveyor belt totransport food products through a heated cooking tunnel which hasopenings at each end of the oven through which the conveyor beltsufficiently extends in order for the operator to start incoming foodproduct on one end, and retrieve the finished cook product from theother. These conveyor oven tunnels are generally open at each end and ininstances wherein microwave energy is used, long entrance and exittunnels are required in order to reduce the amount of microwave energyexiting the tunnel ends. Pizza output capability for such a largeconveyor oven is generally approximately 100 to 120 medium pizzas perhour.

Although cooking speed is important, food quality is also veryimportant. Quality is generally highest when the food product is cookedand presented to the consumer as soon as possible (cooked to order). Assuch, food service operators must provide fast service in addition to ahigh quality food product and pre-cooking and holding food is thereforenot desirable because the quality is substantially less than that of acooked to order food product.

A conveyor oven virtually guarantees that a cooked food product will beremoved from the oven at the proper time, but conveyor ovens have notgenerally been compatible with some type of food service operations suchas: quick service restaurant (QSR); consumer operated ovens where theconsumer is a retail customer at a retail location such as a conveniencestore; or retail foodservice locations with no room for a large conveyoroven, to name a few.

SUMMARY

It has now been found that the above objects are obtained in a conveyoroven with at least one cooking zone and employing gas flow to cook, orre-thermalize a food product. The gas flow to the food product is suchthat conflicting and colliding gas flows produce high heat transfer atthe food product surface. Our conveyor oven may also utilize microwaveenergy, or other means such as radio frequency, induction and otherthermal means, to further heat the food product. Microwave producingmagnetrons are used with side wall mounted microwave waveguidesemploying the use of slotted antenna, although it is not necessary thatthe microwave system launches from the oven cavity side walls and indeedlaunching microwaves from other oven cavity surfaces may be employed.Our conveyor oven may operate as a conventional speed, an acceleratedspeed or a speed cooking conveyor oven. the speed cooking conveyor ovenis described herein as an exemplary embodiment or version. The speedcooking conveyor oven has a cooking tunnel with one or more discretecooking zones and conveyor transport means that moves or indexes foodproduct through the cooking tunnel with product loading and unloadingareas located prior to and after the cooking tunnel. The conveyorloading area for food product is sized such that the available area forfood product is smaller than the area of each cook zone of the cookingtunnel. Gas flow and microwave energies (when microwaves are used) aredistributed to the food product in a manner that produces uniformcooking and heating and a typical cook zone temperature range may be inthe approximately 375° F. (190 degrees Celsius “C.”) to approximately500° F. (260° C.) range, although cook zone temperatures below 375° F.(190° C.) and above 500° F. (260° C.) may be utilized. Gas flowthroughout the cooking tunnel is common to all cook zones and a commonheating means provides hot gas for the cooking tunnel. Cooking controlspermits a wide variety of food products to be run sequentially throughthe cooking tunnel with each food product having a unique cookingprofile, or recipe, that will be executed in a sequential format as thefood product moves, or indexes, through the cooking zones. The indexingconveyor of the exemplary embodiment operates at a fixed rate, that is,each cook zone holds food product for the same length of time, but theindexing time may vary or may be altered or otherwise set according tothe needs of the operator.

An optimum speed cooking conveyor oven will maintain the convenience ofa conventional conveyor oven but cook a fresh food product such as amedium pizza to a high quality level in less than 3 minutes, therebyrepresenting an approximately fifty percent decrease in cooking timeover the conventional conveyor oven. The more than double increase inproduction rate of our invention over the conventional conveyor ovenrepresents a significant decrease in cooking time and may allow afoodservice operation to increase the number of customer served by:adding a drive-through operation; increasing table service turn rates;implementing a consumer operated conveyor oven, or enabling a quickwalk-in/take out function, to name a few. For operations that currentlyrequire multiple ovens to meet customer demand, the significantlyreduced cook times of our speed cooking conveyor oven permits the samecollective food throughput with fewer ovens.

In addition to such items as pizza, our invention is capable of warmingand cooking a wide variety of foods such as seafood, Mexican food, hotdogs, sausage, sandwiches, casseroles, biscuits, muffins, french fries,fresh and frozen appetizers, fresh proteins, pies, bread products, andindeed, any food product that can be cooked in a conventional oven.Generally, conventional conveyor ovens do not have a tall cooking tunnelbut because different food products are of varying volumes, heights andsize profiles, a tall cooking tunnel is desirable for cooking variousfood products and the cooking tunnel of our invention allows for suchcooking of various food products. It is also desirable to keep energyconsumption as low as possible. In order to accomplish reduced energycosts, our invention utilizes recycling gas flow and reduces heat lossfrom the tunnel ends. Not only is energy savings a benefit, reduction ofheat loss from the tunnel ends improves the effective energy transfer tothe food product. Our speed cooking conveyor oven is also simple andsafe to operate, easy to clean and maintain, easy to service and lowcost to manufacture.

Accordingly, it is an object of the present invention to provide aconveyor oven capable of cooking and warming a broad variety of foodproducts with varying size and volume profiles either at conventional orspeed cooking times.

A further object is to provide such a conveyor oven that is energyefficient, simple and safe to operate, simple and easy to clean, easilyserviceable and has a low manufacturing cost.

Still another object is to provide such a conveyor oven that is capableof cooking high quality food product within metal pans, pots, sheet pansand other metal cooking devices commonly found in residential,commercial and vending venues.

It is a further object to provide such an oven with a microwavedistribution system which is more cost effective to manufacture and easyto clean and maintain.

Yet another object is to provide such a microwave distribution systemthat is reliable due to improvements and simplifications.

Still another object is to provide such an oven that can be easily andquickly programmed by an operator to cook various food products with thetouch of a button or such an oven that automatically inputs cookingrecipes into a controller without human intervention.

Additional objects, features and advantages of the present inventionwill become readily apparent from the following detailed description ofthe exemplary embodiment thereof, when taken in conjunction with thedrawings wherein like reference numerals refer to corresponding parts inthe several views.

DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa preferred mode of use, further objectives and advantages thereof, willbest be understood by reference to the following detailed description ofan illustrative embodiment when read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a front view of the conveyor oven of the present inventionillustrating gas flow supply;

FIG. 2 is a front view of the conveyor oven of the present inventionillustrating gas flow return;

FIG. 3 is a top view of the conveyor oven of the present invention;

FIG. 4 is top view of the conveyor oven of the present inventionillustrating product location relative to cook zones;

FIG. 5 is an end view of the cooking tunnel of the conveyor oven of thepresent invention;

FIG. 6 schematically represents gas flow nodes for the conveyor oven ofthe present invention;

FIG. 7 is a front view of the ingress door microwave containmentmechanism of the conveyor oven of the present invention;

FIG. 8 is a front view of the front side section illustrating amicrowave slot antenna;

FIG. 9 is an exploded view of the microwave slot antenna of FIG. 8.

FIG. 10 is an end view of the front side of the conveyor ovenillustrating gas flow deflecting means;

FIG. 11 is an end view of the back side of the conveyor ovenillustrating gas flow deflecting means;

FIG. 12 illustrates the bleed gas flow of the conveyor oven of thepresent invention.

DESCRIPTION

The oven of the exemplary embodiment is shown as a three cook zone speedcooking commercial conveyor cooking appliance wherein each cook zone isshown to be manufactured in the same manner, although it is notnecessary that each cook zone be the same and indeed in some instancesit may be desirable that one or more cook zones be made differently. Ourconveyor oven may be built in other embodiments because it is scalableup or scalable down. The term “scalable” herein means that additionallarger or smaller versions may be developed, and each embodiment orversion may have different size characteristics and utilize differentvoltages of electricity; various forms of electric resistance heatingmeans, or utilize other thermal sources such as natural gas, propane orother thermal means to heat the gas.

As used herein, the terms “magnetron”, “magnetron tube” and “tube” havethe same meaning; the terms “slot” “slots” and “antenna” have the samemeaning; the term “commercial” includes, but is not limited to thecommercial food service industry, restaurants, fast food establishments,speed service restaurants, convenience stores (to list a few) and othermass feeding establishments; the term “residential” refers, generallyspeaking, to residential applications (home use), although the term isnot limited to residences only, but refers to non-commercialapplications for the speed cooking oven and our speed cook conveyor ovenis not limited to commercial uses only, and is equally applicable forvending, residential and other cooking uses; the terms “oven zone” and“oven cavity” have the same meaning and the term “gas” refers to anyfluid mixture, including air, nitrogen and other mixtures that may beused for cooking and applicant intends to encompass within the languageany gas or gas mixture existing or developed in the future that performsthe same function. The term “cook zone” refers to a separate anddiscrete cooking area within the oven cooking tunnel and the term“cooking tunnel” refers to that area of the conveyor oven whereincooking takes place. For example, in a one cook zone speed cookingconveyor oven, there will exist one cook zone and one cooking tunnel. Ina two cook zone speed cooking conveyor oven there will exist two cookzones but only one cooking tunnel, and so on. The means for moving thefood product through the speed cooking conveyor oven is referred toherein as the “conveyor transport means”. The terms “dwell time” and“cook time” have the same meaning. and the terms “conventional cooking”and “conventional means”, have the same meaning and refer to cooking atthe quality level and at the speed that is currently widely utilized. Byway of example, the “conventional cooking time” for a fresh 10-12 inchpizza through a conventional oven is approximately 7 minutes (e.g.conventional cooking time). The term “cooking by-products” refers tosmoke, grease, vapors, small aerodynamic grease particles, odors, andother products caused by the cooking process and the term “odor filter”does not refer exclusively to filtering of odors, but instead refersgenerally to filtering, reduction of, removal of or catalyticdestruction of by-products of the cooking process.

As used herein, the term “rapid cooking” and “speed cooking” have thesame meaning and refer to cooking at five to ten times faster, and insome instances more than 10 times faster than conventional cooking. Theterm “accelerated cooking” has the meaning of cooking at speeds fasterthan conventional cooking but not as fast as speed cooking.

The exemplary embodiment employs the use of an indexing conveyortransport means wherein the operating speed or feed rate is fixed,meaning that each cook -zone holds food product for the same length oftime. The dwell time may be varied or fixed, may be altered eithermanually or by controller 334 (see FIG. 3), and is not limited. Theindexing motion of the conveyor transport means is a cycle consisting ofa traverse to move food product to the next cook zone followed by adwell or cooking period wherein the food product is stopped within acook zone. This indexing motion insures that the energy delivered to thefood product may be individualized for each food product. Control of theenergy applied to the food product is important particularly in thoseinstances wherein the conveyor oven is to cook a variety of foodproducts successively and the cooking profile, or cook recipe must beadjusted as the different food products enter the oven tunnel. Theconveyor oven may operate as a conventional, accelerated or speedcooking conveyor oven.

Appliance 301 includes cook zones 380, 381 and 382 within cooking tunnel394, FIG. 4. The cook zones may be spaced together or a distance apart,depending upon the particular conveyor oven that is desired. Each cookzone is generally defined by an oven cavity 302, FIG. 5, a top wall 303,a bottom wall 304, a front side wall 305 and a back side wall 306. Frontwall 305 is comprised of top gas discharge plate 323 a, microwavelauncher 320 a (when microwaves are utilized) and lower gas dischargeplate 327 a. Back side wall 306 is comprised of top gas discharge plate323 b, microwave launcher 320 b (when microwaves are used) and lower gasdischarge plate 327 b, FIG. 5. In those instances wherein microwaveenergy is not utilized in the conveyor oven, front and back side walls305 and 306 may be comprised of a sheet of metal instead of front ofwaveguides 320 a and 320 b. Oven cooking tunnel 394 has associatedtherewith a movable ingress door 398 and a movable egress door 397,FIG. 1. Food product 310, FIG. 4 is placed on conveyor transport means399 for indexed transport through oven tunnel 394. As previouslydescribed, indexed motion is not required and a continuous transportmeans may be utilized in those instances wherein microwave energy isused and means other than ingress and egress doors are employed in orderto contain the microwave energy within cooking tunnel 394. Althoughdoors 397, 398 are shown as movable vertically relative to the conveyortransport means, other door opening and closing means may be employed;such as side-hinged doors, top hinged doors or doors utilizing otherattachment means, and applicant does not intend to be limited but ratherintends to encompass within the language any structure presentlyexisting or developed in the future that performs the same function asdoors 397, 398.

The conveyor oven is comprised of two independent gas transfer systems,described herein as a front gas transfer system and a back gas transfersystem, wherein the front gas transfer system 393 a delivers gas to andfrom the front side of cook zones 380, 381, 382, FIG. 3, and back gastransfer system 393 b delivers gas to and from the back side of the cookzones 380, 381, 382. Cook zones 380, 381, 382 may also have associatedtherewith vent tube 371, FIG. 5, which allows for the passage of ventgas from any one, or all, of cook zones 380, 381, 382 to atmosphere.Affixed within vent tube 371 may be vent odor filter 372, which providesfor the removal of cooking by-products. Vent odor filter 372 may be madeto be removable for cleaning or replacement and various materials,including catalytic materials, may be utilized to accomplish odorremoval. In some instances, varying efficiencies of said materials mayalso be employed in order to allow various amounts of odors to escapethe oven cavity.

Referring again to FIG. 3, gas is transferred to cook zones 380, 381,382 via front gas transfer conduit 393 a extending from gas flow means316 a to first cook zone 380, then continuing to second cook zone 381and terminating with third cook zone 382, FIGS. 1, 3. In fluidconnection with front conduit means 393 a are gas flow nodes 390 a, 391a, 392, FIG. 6, which allow for the passage of gas from gas transferconduit 393 a to top gas transfer section 317 a, FIG. 5, of each cookzone 380, 381 and 382. In fluid connection with top gas transfer section317 a is top gas egress opening 312, FIG. 2, within each cook zone,which is open to, and in fluid connection with oven zone 302 through topwall 303. Top gas egress opening 312 is substantially rectangular,although other geometries may be employed, and is centrally locatedwithin each oven top wall 303 and provides for the passage of gas fromoven zone 302 into return conduit means 389, FIG. 1 which returns gasfrom oven zone cook zones 380, 381, 382 to gas flow means 316 a as gasesare removed from oven zone 302 through top egress gas egress opening312. Located within each top gas egress opening 312 may be greaseextractor 313, FIG. 2. As gas is drawn through top gas egress opening312 of each oven zone, the gas passes across grease extractor 313, whichremoves the larger grease particles. By extracting the larger greaseparticles managing grease build-up in the down stream conduits andheater area is simplified. It may be desirable for each cook zone toutilize grease extractor 313, or alternatively no grease extractor, orstill further additional grease extractors may be placed throughout thegas flow path.

During normal cooking it may be desirable for one food product to becooked after another different type of food product with successivecycles continuing. For example a food product such as shrimp may becooked first, followed by a baked product or pastry. Without appropriatefiltration, the cooking by-products will contaminate the baked product,producing an undesirable taste and odor in the pastry. Although greaseextractors 313 may be utilized, further gas filtration may be desirableand odor filters 343, FIG. 2 may be placed within any or all cook zonesor within the oven tunnel and may be placed upstream of blowers 316 a,316 b to be discussed further herein, and may be made of variousmaterials including catalyst materials such as a corrugated foil coatedwith catalyst, or catalyst coated screens. The catalyst acts to combust(oxidize) the cooking by-products. Such catalyst materials may alsoinclude, but is not limited to: activated charcoal, zeolite or ultraviolet wavelight light. It is beneficial that the odor filters becomprised of a material, or materials, that effectively scrubs, orcleans the gas flow with a minimal amount of interference with the gasflow velocities and it is beneficial that the odor filters be easilyremoved, easily cleaned and inexpensive for the operator to replace. Themost efficient utilization of the spent hot gas from cook cavity 302 isby re-circulation of the gas through the oven tunnel many times during acooking cycle. In some uses, it may be desirable to utilize additionalodor filters, which may be placed anywhere within the gas flow path.Depending upon the various levels of cooking by-product control that maybe desired depending upon the food products to be cooked, the particularuse of the oven, or the requirements of regulatory agencies, or otherfactors, in order to minimize cooking by-products within each oven zone,the oven tunnel or the gas flow supply and return conduits may thereforeinclude one odor filter per appliance 301, “n” number of odor filters asdetermined by “n” cook zones, or more than “n” number of odor filters.

As used herein the term “upstream” refers to a location within the gasflow path that comes before gas flow means 316 a and 316 b. For example,gas that is supplied to gas flow means 316 a, 316 b is upstream of gasflow means 316 a, 316 b and gas that is discharged from gas flow means316 a, 316 b is downstream of said gas flow means. The exemplaryembodiment illustrates gas flow means as blower wheels 316 a, 316 b,although our invention may utilize a single gas flow device, such as asingle blower wheel and applicant intends to encompass within thelanguage any structure presently existing or developed in the futurethat performs the same function as 316 a, 316 b. Blower wheels 316 a,316 b act much like centrifugal separators that will separate andcoalesce the small grease particles in the blower scroll area anddischarge larger particles into the supply area.

In an alternate embodiment, a portion of the gas flow leaving gas flowmeans 316 a, 316 b is diverted to the inlet side of gas bleed chamber365 a, 365 b with odor filters 340 located within bleed chambers. Theportion of gas flow diverted to said bleed chamber is referred to hereinas the “bleed gas flow.” The bleed gas flow passes through odor filter340, FIG. 12 shown as a catalytic converter, where a portion of thecooking by-products is oxidized. Cleaner gas leaving odor filter 340 iseither reintroduced into the gas flow stream or is vented to atmospherevia vent tube 371. Odor filter 340 will remove the desired amount ofgrease during a single pass as the small bleed gas flow will continuallyremove grease generated during cooking. Indeed, in some embodiments itmay be desirable for the odor filter to remove all, or as much cookingby-product as possible. Varying destruction efficiencies of odor filter340 will produce varying results and in those instances wherein odorfilter 340 is of the catalytic type, destruction efficiencies of greaterthan 50% have shown to produce acceptable results. The bleed gas flow isconfigured as an internal cleaning gas loop operating separate from themain gas flow to oven tunnel 394. In those instances wherein odor filter340 is a high efficiency catalytic type filter for high cookingby-product destruction efficiencies, a large pressure drop may occuracross odor filter 340. Space velocities for the catalytic converterrange are typically in the range between approximately 60,000/hr to120,000/hr depending on the catalyst material utilized, the amount ofcooking by-product loading in the gas stream and odor filter 340 inletambient temperature. Unlike the placement of odor filter 343 in the maingas flow which results in a significant pressure drop on the entirere-circulating gas flow, the use of bleed gas catalytic type filters, orother odor filters, does not significantly reduce gas flow systempressure to oven tunnel 394. The small bleed gas flow utilizes nearlythe entire pressure capability of the gas flow means through the gasbleed system, thereby permitting the use of catalytic materials requiredfor a high destruction efficiency, based on one pass through odor filter340. Additionally, the small bleed gas odor filters 340 are easilyinstalled, can be placed in convenient locations and readily accessible.Bleed gas flows are a fraction of the main gas flow to the oven tunnel,therefore significant inlet gas temperature preheat may be achieved.Placing small gas pre-heaters 341 a, 341 b, FIG. 12 prior to odorfilters 340 within the bleed gas flow system may additionally providesubstantial improvement in the destruction efficiency of odor filter340. Pre-heaters 341 a, 341 b are capable of increasing the gas inlettemperature by greater than 100° F. (37.78° C.) and this temperatureincrease in the bleed gas to odor filter 340 makes it possible toachieve the desired destruction efficiency with less catalyst material.In some instances a main gas flow odor and cooking by-product clean-upsystem may have difficulty cleaning the gas when oven set point is underapproximately 425° F. (218.3° C.). Pre-heaters 341 are capable ofproducing cooking by-product control with oven tunnel temperatures below350° F. (176.67° C.). Additional appliance flexibility is achieved bysimultaneously permitting lower oven cook temperature setting whileproviding grease control.

The bleed gas flow is approximately 10% of the total gas flow, blowers316 a, 316 b, and pre-heaters 341 a, 341 b would each provideapproximately 600 watts of heat for a 100° F. (37.78° C.) rise in gasinlet temperature. The combined 1200 watts of heating is less than onethird of the total heat required for each oven zone of conveyor oven andis very close to the heat needed to satisfy standby losses of the oven(i.e., heat loss due to conduction, radiation, vent losses to ambient).As such, the pre-heaters can be the primary gas heaters with the larger(for this example 3000 W) main gas heater used to satisfy cooking needs.

As previously described, in fluid connection with, and located withinreturn conduit means 389 is a front gas flow means, illustrated as frontblower wheel 316 a, FIGS. 1,5. Our invention may utilize variable speedblower motors and variable speed blower motor controllers, but there isno requirement for their use and indeed the conveyor oven of the presentinvention may avoid the problems and complexity of variable speed blowermotors by maintaining a constant gas flow, or alternatively, asubstantially constant gas glow rate through the oven zones, oven tunneland gas transfer and gas delivery systems. The gas flow may be veryaggressive, or less aggressive, depending upon the cooking requirementsfor each food product and one means to achieve gas flow modulation is byuse of a gas pumping means such as a blower motor, blower wheelcombination, utilizing a controller or a multi speed switch that allowsfor the switching of the blower motor speed in pre-determined fixedincrements. Other gas flow means may be utilized to accelerate the gasflow, and applicant intends to encompass within the language anystructure presently existing or developed in the future that performsthe same function as 316 a, 390 a, 391 a and 316 b, 390 b and 391 b, tobe discussed further herein. Connected to front blower wheel 316 a isblower motor shaft 390 a, which is direct drive with electric motor 391a, FIG. 5. Other means may be employed for coupling blower wheel 316 ato electric motor 391 a, such as belt drive and the drive means is notlimited to direct drive and applicant intends to encompass within thelanguage any structure presently existing or developed in the futurethat performs the same function. Blower wheel 316 a takes gas fromreturn conduit means 389 and delivers the gas via conduit means 393 a tonode sections 390 a, 391 a, 392 a, FIG. 6. Within node sections 390 a,391 a, 392 a are gas flow control means 388 a, FIG. 1, which allow forthe passage of gas from conduit means 393 a to gas transfer section 317a of each oven zone. Gas flow control means 388 a may allow for thepassage of varying quantities of gas, or no gas, to transfer section 317a of each cook zone and are shown as valves 388 a, although other meansmay be employed in order to allow, limit or restrict the gas flow toeach oven zone 380, 381, 382 by nodes 392 a, 391 a, 390 a and applicantintends to encompass within the language any structure presentlyexisting or developed in the future that performs the same function asvalves 388 a.

Top front gas transfer section 317 a, FIG. 5, is in fluid connectionwith a lower front gas transfer section 318 a via a front vertical gastransfer section 319 a. Front vertical gas transfer section 319 a isbounded by front side wall 366 and a front microwave waveguide section320 a, when microwaves are used. When microwaves are not used, waveguidelauncher 320 a may be replaced by metal. As can be seen in FIG. 5, asgas is supplied into top front gas transfer section 317 a, the gas isdischarged through a top front gas discharge plate 323 a into oven zone302 via apertures 300 a and onto the front top and front side portion offood product 310. Apertures 300 a may be slotted, regularly formed orirregularly formed apertures and are illustrated herein as nozzles 300 aand 300 b, 329 a, 329 b, FIG. 5, and applicant intends to encompasswithin the language any structure presently existing or developed in thefuture that performs the same function as 300 a, 329 a and 300 b and 329b, discussed further herein. Gas that has not been discharged throughtop front gas discharge plate 323 a flows to lower front gas transfersection 318 a via vertical transfer section 319 a. Gas that isdistributed to lower front gas transfer section 318 a may be re-heated,if desired, by a lower front heating means 303 a, FIG. 5, before saidgas passes through slotted or perforated lower front gas discharge plate327 a via apertures 329 a, for discharge onto the front bottom and frontside portions of food product 310 in oven zone 302. Lower front heatingmeans 303 a may be present in some embodiments and not present in othersdepending upon the particular requirements for the speed cookingconveyor oven. Although lower front heating means 303 a is shown as anelectric open coil heater, other means to heat the gas may be utilizedsuch as other types of electric heating means, electric resistanceelements, natural gas, propane or other heating means and applicantintends to encompass within the language any structure presentlyexisting or developed in the future that performs the same function as303 a and 303 b to be discussed further herein. Apertures 300 a and 329a are sized for a low pressure drop, while providing and maintainingsufficient gas velocities in the range of approximately 2000 ft/minute(609.6 meters/minute) to approximately 6000 ft/minute (1828.80meters/minute) to properly cook the food product as described herein. Insome instances, velocities below 2000 ft/minute (609.6 meters/minute) orabove 6000 ft/minute (1828.80 meters/minute) may also be utilized,depending upon the particular food product to be cooked, or a particularcooking recipe that the controller is executing, to be discussed furtherherein, and applicant does not intend to limit the invention to gasvelocities within a particular range. Apertures 300 a are sized suchthat the majority of the gas is supplied from top front gas dischargeplate 323 a. The resulting imbalance of gas flows between the top frontgas discharge plate 323 a and lower front gas discharge plate 327 a isdesirable because the top flows must aggressively remove moistureproduced and escaping from the top and top side surfaces of the foodproduct 310. The gas flow imbalance also serves to heat, brown and/orheat and brown the food product 310.

Referring again to FIG. 3, gas is transferred to the back of cook zones380, 381, 382 via a back gas transfer conduit 393 b, FIG. 3, extendingfrom gas flow means 316 b to first cook zone 380, then continuing tosecond cook zone 381 and terminating with third cook zone 382, FIGS.1,3, in the same manner as previously described for front gas transfersection 393 a. In fluid connection with back conduit means 393 b are gasflow nodes 390 b, 391 b, 392 b, FIG. 6, which allow for the passage ofgas from gas transfer conduit 393 b to top gas transfer sections 317 b,FIG. 4, of each cook zone 380, 381 and 382. In fluid connection with topgas transfer section 317 b is the previously described top gas egressopening 312, which is in fluid connection with return conduit means 389b. Return conduit means 389 b is in fluid connection with a back gasflow means, illustrated as back blower wheel 316 b, FIG. 3. As withblower wheel 316 a, other devices may be utilized for gas flow means 316b to accelerate the gas flow, and applicant intends to encompass withinthe language any structure presently existing or developed in the futurethat performs the same function. Connected to back blower wheel 316 b isblower motor shaft 390 b, which is direct drive with electric motor 391b, and as with electric motor 391 a other means may be employed forcoupling blower wheel 316 b to electric motor 391 b. Blower wheel 316 btakes gas from oven zone 302 via common return conduit means 389 anddelivers the gas via conduit means 393 b to node sections 390 b, 391 b,392 b, FIG. 6. Within node sections 390 b, 391 b, 392 b are gas flowcontrol means 388 b, FIG. 5, which allow for the passage of gas fromconduit means 393 b to transfer section 317 b of each oven zone. As withgas flow control means 388 a, flow control means 388 b, FIG. 5, mayallow for the passage of no gas, or varying quantities of gas totransfer section 317 b and are shown as valves 388 b although othermeans may be employed in order to limit or restrict the gas flow to eachoven zone 380, 381, 382 and applicant intends to encompass within thelanguage any structure presently existing or developed in the futurethat performs the same function as valves 388 b.

Top back gas transfer section 317 b, FIG. 5, is in fluid connection witha lower back gas transfer section 318 b via a back vertical gas transfersection 319 b. Back vertical gas transfer section 319 b is bounded byback side wall 367 and back microwave waveguide section 320 b. As can beseen in FIG. 5, as gas is supplied into top back gas transfer section317 b, the gas is discharged through a top back gas discharge plate 323b into oven zone 302 via apertures 300 b and onto the back top and backside portion of food product 310. Apertures 300 b may be slotted,regularly formed or irregularly formed apertures and are illustratedherein as nozzles 300 b and 329 b, FIG. 5, and applicant intends toencompass within the language any structure presently existing ordeveloped in the future that performs the same function as 300 b and 329b. Gas that is distributed to lower back gas transfer section 318 b maybe re-heated, if desired, by a lower back gas heating means 303 b, FIG.5, before said gas passes through slotted or perforated lower back gasdischarge plate 327 b via apertures 329 b, for discharge onto the backbottom and back side portions of food product 310 in oven zone 302.Lower back gas heating means 303 b may be present in some embodimentsand not present in others depending upon the particular requirements forthe speed cooking conveyor oven and as with gas heating means 303 a,previously described, may be made of any material that accomplishesheating of the gas. Apertures 300 b and 329 b are sized for a lowpressure drop, while providing and maintaining sufficient gas velocitiesin the range of approximately 2000 ft/minute (609.6 meters/minute) toapproximately 6000 ft/minute (1828.8 meters/minute) to properly cook thefood product as described herein. In some instances, velocities below2000 ft/minute (609.6 meters/minute) and above 6000 ft/minute (1828.8meters/minute) may also be utilized. Apertures 300 b are sized such thatthe majority of the gas is supplied from the top back gas dischargeplate 323 b. As with the front gas system, the resulting imbalance ofgas flows between the top back gas discharge plate 323 b and lower backgas discharge plate 327 b is desirable because the top flows mustaggressively remove moisture produced and escaping from the top and topside surface of the food product 310. The imbalance also serves to heat,brown and/or heat and brown the food product 310.

The front and back gas supply systems, although independently describedherein, are the same configuration and function to uniformly circulatehot gas flow across the top and top sides and bottom and bottom sides ofthe food product, and return the gas to the heating mechanism and gasflow means for re-delivery to the oven zones. Although the sameconfiguration is shown in the exemplary embodiment no requirement existsfor this symmetry and the front gas supply system may be configureddifferently than the back supply system, and the top gas supply systemsconfigured differently from the bottom. Indeed, each cook zone may beconfigured differently than the other cook zones and many combinationsof configurations may be desirable for the particular conveyor oven.When a single cook zone conveyor oven is desired, various combinations,as previously described may also be utilized.

As previously described, gas flow is delivered via four gas transfersections 317 a, 317 b, 318 a, 318 b which are located in the top andbottom corners of each oven cavity 302 as shown in FIG. 5. Gas flowtransfer sections 317 a, 317 b; 318 a and 318 b extend the width of eachoven zone 302, although it is not required that the gas flow transfersections extend the entire length of the oven zone. Gas transfer section317 a is located in the top front corner of oven zone 302, FIG. 5, wheretop wall 303 intersects oven zone front side wall 366; gas transfersection 317 b in the top back corner where top wall 303 intersects backside wall 367; gas transfer section 318 a in the lower front corner ofthe oven zone 302 where bottom wall 304 intersects front side wall 366;and gas transfer section 318 b in the lower back corner where bottomwall 304 intersects back side wall 367. Each gas transfer section issized and configured to deliver the appropriate gas flow for theparticular oven utilized. For example, in a smaller oven, the gasdelivery sections, indeed the entire oven, may be sized smaller inproportion to the smaller footprint of the particular requirements, anda larger oven may have proportionally larger gas delivery sections.

As seen in FIG. 5, the front side and the back side gas flows convergeon food product 310 creating an aggressive gas flow field on the foodproduct surface that strips away the moisture boundary layer. Thisturbulently mixed gas flow directed at the food product can best bedescribed as glancing, conflicting and colliding gas flow patterns thatspatially average the gas flow over the surface area of the food productproducing high heat transfer and moisture removal at the food productsurface, thereby optimizing speed cooking. The gas flow is directedtowards the top, the bottom and the sides of the food product from thefront and back sides of the oven zone and the front and back side gasflows conflict, collide and glance off each other at the food productsurface before exiting the oven zone through top gas egress opening 312.As used herein the term “mixing” refers to the glancing, conflicting andcolliding gas flow patterns that meet at and upon the top surface, thebottom surface and the front and back side surfaces of the food productand produce high heat transfer for both conventional and speed cookingof the food product due to spatial averaging of the gas flow heattransfer. The mixing gas flows patterns are created within the oven zoneand, when appropriately directed and deflected, produce a high qualitycooked food product that can also be cooked very quickly. Although speedcooking of high quality food product may be accomplished with thisinvention, conventional cooking may also be accomplished by adjustingthe gas flow and microwave energy (in instances wherein microwave energyis utilized) to the food product; or by use of gas flow alone with nomicrowave energy. Enhancing the highly agitated, glancing, conflicting,and colliding gas flow is the general upward flow path the gas willfollow, as shown in FIG. 5 through top gas egress opening 312, as thegas exits the top of oven zone 302. This upward gas flow draws also thegas from lower gas discharge sections 318 a and 318 b thereby scrubbingthe bottom of the food product, pot, pan or other cooking vessel, bypulling gas flow around the sides of said vessel, further enhancing theheat transfer, as well as drawing the gas that scrubs the upper surfaceup towards the oven zone top wall.

Returning to FIG. 5, top gas discharge plates 323 a and 323 b arepositioned within oven zone 302 such that the gas flow from top gastransfer section 317 a conflicts and collides with the gas flow from topgas transfer section 317 b upon the food product surface and strikes thefood product at an angle that is between zero degrees and 90 degrees asreferenced from the horizontal top wall (where zero degrees is parallelto the horizontal top wall) and lower gas discharge plates 327 a and 327b are positioned within oven zone 302 such that the gas flow from lowergas transfer section 318 a conflicts and collides with the gas flow fromlower gas transfer section 318 b upon the lower surface of the foodproduct at an angle that is between zero degrees and ninety degrees asreferenced from the horizontal bottom wall. Various cooking requirementsmay require that the angle of the gas discharge plates 323 a, 323 b, 327a and 327 b be adjusted, either during manufacture, or adjustable withinthe oven after manufacture, in order for the chef or cook to change gasflow velocity angles (vectors) to effect different cooking profiles.

The number and placement of the apertures 300 a, 300 b, 329 a and 329 bwill vary according to the particular oven that is desired. For example,a general purpose speed cooking conveyor oven may be scaled to a bakingoven by changing the number of apertures, which may be fewer in numberbut be larger in size, thereby allowing for a more gentle gas flowacross the food product, and producing proper delicate baking of thefood product. If a browning oven were desired, the apertures may be morenumerous and smaller in diameter. Additionally, the operator may desiremore flexibility of cooking and in this circumstance gas dischargeplates 323 a, 323 b, 327 a and 327 b may be fabricated in a manner thatallows for quick change-out of the plates by the operator. As usedherein the term “aperture” refers to irregular slots, irregular holes orirregular nozzles, regularly formed slots, regularly formed holes orregularly formed nozzles or a mixture of regularly formed andirregularly formed slots, holes or nozzles. FIG. 5 illustrates the useof three rows of apertures 300 a and 300 b on top gas delivery sections317 a and 317 b, and two rows of apertures on the lower gas deliverysystems 318 a and 318 b, although more or fewer rows and numbers ofapertures may be utilized and applicant intends to encompass within thelanguage any structure presently existing or developed in the futurethat performs the same function. The gas delivery system as illustratedin FIG. 5 produces aggressive glancing, conflicting and conflicting gasflow patterns 330 a and 330 b wherein an aggressive top glancing,conflicting and colliding gas flow pattern 330 a also interacts with thefront top portion and front top side portion of food product 310 and asimilar back top glancing, conflicting and colliding gas flow pattern330 b interacts with the back top portion and top back side portion offood product 310. Aggressive glancing, conflicting and colliding gasflow 331 a interacts with the lower front and side portions of the foodproduct and gas flow 331 b interacts with the lower back and sideportions of the food product. This cooking profile creates high heattransfer capability by using the surface of the food product, as well asthe interference of flow fields to minimize boundary layer growth. Afterthe aggressive glancing and conflicting gas flow patterns 330 a and 330b contact or strike the food product they are exhausted through topegress section 312 and cycle back through the oven as described herein.The highly turbulent flow of the conflicting gas patters describedherein has several benefits. First, the conflicting gas flow patternscreate cook zone gas flow that is averaged spatially, or a flowcondition that tends to average out the high and lows in flow variationfor a given point in the cook cavity greatly reduces the designcomplexity needed to impose a uniform flow field over a cooking zone. Inthose instances where gas transfer sections 317 a, 317 b, 318 a and 318b are in use, conflicting gas flows produce an “X” style gas flowwherein high heat transfer rates needed for speed cooking average theflow conditions over space and time, thereby producing uniform cookingand browning.

Another advantage of the upward return gas path is that a conveyortransport means may pass through the cook zones because the two ends ofcook cavity 302 are now free of any gas flow means or microwave relatedsubsystems (i.e., no blower return gas path or microwave feeds). Also,uniform side browning is effected because the bottom gas flow is drawnpast the food product edges as the gas flows up to egress point 312within roof 303. Third, grease loading in the return gas stream isreduced.

Gas flow control to the various zones is accomplished via simple gasflow dampers or valves, referred to as nodes 390 a, 390 b, 391 a, 391 b,392 a, 392 b. This approach maintains a relatively constant flow throughthe oven thereby eliminating the need for varying the blower speed. Thegas flow within the conveyor oven, as well as other functions of cookingappliance 301 are directed by controller 334, FIG. 3. Speed cooking ofindividual food products generally requires a separate cooking profileor recipe for that food product. The speed cooking conveyor oven of theexemplary embodiment is capable of cooking various food products at thesame time, therefore the oven controls must track the food products asthey move through the cook zones and adjust the gas flow energies, andmicrowave energies (when microwave energy is used) of each cook zoneaccording to the cooking recipe that has been input by the operator orinput by a scanning device, or other device for each food product. Thecooking profile for a food product, referred to herein as the “cookingrecipe” may be quite complex and time and labor expense associated withinputting cooking recipes may be minimized by use of controller 334loaded with predetermined cooking recipes from a smart card, or loadedfrom an automated product identification device, or other scanning andreading devices may be utilized. Alternate embodiments will allow theoperator to place the food product onto conveyor means 399 in loadingzone 396, FIG. 4 and a unique product identification code could be usedto transfer recipes to the oven controller, thereby eliminating manualcooking recipe inputs. Alternatively, manual single button entries, ormultiple button entries may be made by the operator to input the cookingrecipes and applicant does not intend limitations concerning the use ofthe control system for cooking recipes. Indeed optical scanners may beutilized at the ingress end of appliance 301. The exemplary embodimentdescribes a unique product identification code that is encoded with thecorrect cooking recipe settings for each food product and the transferof information is accomplished using an Radio Frequency Identification(“RFID”) tag placed on the food or food packaging. The RFID tag may beprogrammed from the restaurant point of sale system and read by the ovencontroller by any means known such as cable linked one waycommunication, two way communication, wireless or other means andapplicant intends to encompass within the language any structurepresently existing or developed in the future that performs thecommunication function. Reading of the RFID tag by controller 334minimizes error associated with the operator imputing an incorrect ovencooking recipe and allows the restaurant to optimize customer service asthe oven controller communicates with the point of sale system duringthe cooking cycle for each food product. Controller 334 determines,among other things, the velocity of gas flow, which may be constant orvaried, or, may be constantly varied throughout the cooking cycle andwhether or not gas is delivered through the previously described cookingnodes to cook zones 380, 381, 382. It may be desired to cook the foodproduct on one velocity throughout the entire cooking cycle, or to varythe gas velocity depending upon conditions such as a pre-determinedcooking recipes, or vary the gas velocity in response to various sensorsthat may be placed within the cooking zone, oven return gas paths orvarious other positions within the oven. The location and placement ofsaid sensors will be determined by the particular application of theoven. Additionally, other means may be utilized wherein data istransmitted back to controller 334, and thereafter controller 334adjusts the cooking recipe in an appropriate manner. For example sensors(temperature, humidity, velocity, vision and gas borne chemical mixturelevel sensors) may be utilized to constantly monitor the cookingconditions and adjust the gas flow, and microwave energy, when used,accordingly within a cooking cycle, and other sensors not describedherein may also be utilized and the speed cooking conveyor oven mayutilize sensors that are not currently commercially practical due tocost or other limitations (such as laser, non-invasive temperaturesensors and other sensors that are currently too expensive to becommercially feasible), and the speed cooking oven is not limited tothose discussed herein, as many sensing devices are known and utilizedin and applicant intends to encompass within the language any structurepresently existing or developed in the future that performs the samefunction. Additionally, controller 334 may control the amount of bleedgas flow through each odor filter 340, as previously described. Forexample, oven zone 380 may contain a food product that, uponconventional cooking, or speed cooking, will produce larger amounts ofairborne grease, smoke and odor than the food products in the othercooking zones. In such an instance, controller 334 may allow for moregas flow to pass through odor filter 340 of oven zone 380 and eitherallow more or less gas flow to odor filters that may be utilized foroven zones 381, 382 and to adjust pre-heaters 341 a, 341 b of oven zone380.

Gas flow may also be adjusted as a function of available power. In theevent, for example, the heating means of an all electric speed cookingconveyor oven is requiring or utilizing a large amount of power (largerthan available power levels which may vary according to location andlocal code and ordinance) it may be desirable for controller 334 toreduce electrical power to the heating means or other electricalcomponents in order to conserve available power. In a speed cookingconveyor oven, some systems may be powered by electric current, but theelectric power requirements will not be as high as required for an allelectric oven because the energy required for gas heating and cookingwill be provided by the combustion of a hydrocarbon based fuel. In thisevent a controller may not be required, indeed knobs or dials may beutilized.

In an alternate embodiment, gas flow control may be accomplished by gasflow control means, FIGS. 10, 11. As gas is discharged into top frontgas transfer section 317 a, a selected portion of said gas may bedirected through apertures 300 a within gas discharge plate 323 a by gasdeflecting means 324 a, shown in the open position, FIG. 10. Gasdeflecting means 324 a is shown as pivotally attached to gas dischargeplate 323 a, although, other means for accomplishing said gas deflectionmay be utilized. For example means such as normally open, normallyclosed, or normally partially open and normally partially closedswitched plates may be used (wherein said plates slide along the insideof perforated plate 323 a to limit the aperture openings 300 a ofdischarge plate 323 a), and applicant intends to encompass within thelanguage any structure presently existing or developed in the futurethat performs the same function as gas deflecting means 324 a. Gas thathas not been discharged or deflected through apertures 300 a flows tolower front gas transfer section 318 a via vertical transfer section 319a. Pivotally attached to waveguide section 320 a (when waveguides areused and to sheet metal when not used) is a lower gas transferdeflection mechanism 352 a, FIG. 10 that operates to limit the amount ofgas that is transferred to lower gas transfer section 318 a. As usedherein, the terms “flow control means” “gas deflecting means” “transferdeflection mechanism” and “flow control means” all have the same meaningand refer to means to control gas flow within and to various parts ofthe conveyor oven. Indeed, certain cooking operations may call for moregas flow to the lower part of the conveyor oven, while other operationswill call for little or no gas flow to the bottom side of the oven fordelivery to the bottom of the food product. In those instances wherelittle or no gas flow is desired upon the bottom surface of the foodproduct, gas transfer deflection mechanism 352 a may be closed in orderto allow all, or substantially all, of the gas flow into top front gasdelivery section 317 a.

Gas that flows to lower front gas delivery section 118 a may bere-heated, if desired, by lower front heating means 303 a, FIG. 10.After passing over heating elements 303 a, the gas may be furtherdeflected by deflecting means 328 a, FIG. 10, shown in the openposition. As gas deflecting means 328 a is rotated, directional controlof the gas flow may be further refined, allowing for gas flow to passthrough the upper or lower rows of apertures of lower gas plate 327 a atvarious positions along food product 310 bottom surface, FIG. 10.Although gas deflecting means 328 a is shown as pivotally attached tofront slotted or perforated gas discharge plate 327 a, gas deflectingmeans 328 a is not limited to the pivotally attached means illustratedherein, and as described elsewhere herein, applicant intends toencompass within the language any structure presently existing ordeveloped in the future that performs the same function as gasdeflecting means 324 a, 352 a, 328 a, 324 b, 352 b and 328 b to bediscussed further herein.

As gas is discharged into top back gas transfer section 317 b, aselected portion of said gas may be directed through apertures 300 bwithin gas discharge plate 323 b by gas deflecting means 324 b, shown inthe open position, FIG. 11. Gas deflecting means 324 b is pivotallyattached to gas discharge plate 323 b, although as with 323 a, othermeans for accomplishing said gas deflection may be utilized. For examplemeans such as normally open, normally closed, or normally partially openand normally partially closed switched plates may be used (wherein saidplates slide along the inside of perforated plate 323 b to limit theaperture openings 300 b of discharge plate 323 b), and applicant intendsto encompass within the language any structure presently existing ordeveloped in the future that performs the same function as gasdeflecting means 324 b. Gas that has not been discharged or deflectedthrough apertures 300 b flows to lower front gas transfer section 318 bvia vertical transfer section 319 b. Shown as pivotally attached towaveguide section 320 b (when waveguides are used and to sheet metalwhen not used) is a lower gas transfer deflection mechanism 352 b, FIG.11 that operates to limit the amount of gas that is transferred to lowergas transfer section 318 b. As with the front gas transfer system,certain cooking operations may call for more gas flow to the lower partof the conveyor oven, while other operations will call for little or nogas flow to the bottom side of the oven for delivery to the bottom ofthe food product. In those instances where little or no gas flow isdesired upon the bottom surface of the food product, gas transferdeflection mechanism 352 b may be closed in order to allow all, orsubstantially all, of the gas flow into top front gas delivery section317 b.

Gas that flows to lower back gas delivery section 118 b may bere-heated, if desired, by lower front heating means 303 b, FIG. 11.After passing over heating elements 303 b, the gas may be furtherdeflected by deflecting means 328 b, FIG. 11, shown in the openposition. As gas deflecting means 328 b is rotated, directional controlof the gas flow may be further refined, allowing for gas flow to passthrough the upper or lower rows of apertures of lower gas plate 327 b atvarious positions along food product 310 bottom surface, FIG. 11.Although gas deflecting means 328 b is shown as pivotally attached tofront slotted or perforated gas discharge plate 327 b, gas deflectingmeans 328 b is not limited to the pivotally attached means illustratedherein, and as described elsewhere herein, applicant intends toencompass within the language any structure presently existing ordeveloped in the future that performs the same function as gasdeflecting means 324 a, 352 a, 328 a, 324 b, 352 b and 328 b.

In those instances wherein directional control of the gas flow isdesired, gas deflecting means 324 a, 324 b, 328 a, 328 b and 352 a and352 b, FIGS. 9, 10 may be rotated such that gas flow is diverted toselected apertures, thereby effecting a different gas flow pattern andgas mixing upon and above the food product surface. Additionally, inthose instances wherein no bottom side gas flow is desired, gasdeflecting means 352 a, 352 b may be closed, thereby allowing for littleor no passage of gas flow to the lower portion of the oven cavity.Various other adjustments of gas deflecting means are possible andapplicant intends to encompass within the language any structurepresently existing or developed in the future that allows forcombinations of open and closed positions of apertures 300 a, 300 b, 329a and 329 b by the various gas flow control means described herein. Gasdeflecting means 324 a, 324 b, 328 a, 328 b and 352 a and 352 b may bemanually controlled, automatically controlled via controller 334,controlled by other mechanical or electrical means, or controlled viacombination of automatic and manual control and applicant intends toencompass within the language any structure presently existing ordeveloped in the future that performs the function described hereinconcerning adjustment of the gas deflecting means. In those instanceswherein gas deflecting means 324 a or 324 b allow little or no gasthrough gas discharge plates 323 a, 323 b, and further wherein littlegas flow is desired through lower gas discharge plates 327 a, 327 b, aby-pass return gas flow conduit may be provided in order to return gasflow to gas return conduit means 389. Additionally, in those instanceswherein gas directing means 328 a, 328 b allow little or no gas throughgas discharge plates 327 a, 327 b and less gas flow is desired throughgas discharge plates 323 a, 323 b, a conduit means may be provided toreturn gas flow to return conduit means 389, or alternatively toatmosphere or to gas bleed system previously described for further odorand grease clean-up. Indeed, various and multiple combinations of gasflow control exist, depending upon the particular oven that is desiredand gas flow may be directed to many and various apertures throughoutthe conveyor oven in order to accomplish the desired finished cookedproduct 310.

The oven of the present invention may also utilize microwave energy toat least partially cook the food product. As seen in FIG. 5, front sidemicrowave launching waveguide 320 a is attached within oven zone 302 tofront side wall 305 between top front gas discharge plate 323 a andlower front gas discharge plate 327 a. Back side microwave launchingwaveguide 320 b is attached within oven zone 302 to back side wall 306between top back gas discharge plate 323 b and lower back gas dischargeplate 327 b. The microwave waveguides are designed to distributemicrowave power from magnetrons 100, FIG. 8, uniformly from the back tothe front of oven cook cavity 302. The vertical distance above cavitybottom wall 304 of waveguides 320 a and 320 b is such that, under normalcooking conditions, approximately more than one third of the microwaveenergy is available below food product 310, with the balance ofmicrowave energy available above food product 310.

As shown in FIG. 5, microwave energy 351 a, 351 b, FIG. 5, is broadcastfrom waveguides 320 a, 320 b into oven zone 302 via a slotted antenna370, FIG. 8, wherein three or four narrow apertures (slots) 370 arespaced along the waveguide. Various configurations for microwavedistribution have been utilized with varying results and less than threeslots may be utilized or more than three slots may be used, andapplicant intends to encompass within the language any structurepresently existing or developed in the future that performs the samefunction. Important to an efficient and inexpensive slotted microwavesystem, FIG. 9 is the slot length 382, slot width, 383, the spacingbetween the slots, slot end spacing, angle of the slot relative to thelong axis of the waveguide, the number of slots per waveguide and theslot orientation.

Slots 370 in waveguides 320 a, 320 b, are open to the cooking cavity andmust be covered or protected so that grease and other contaminantscannot enter the waveguide and a durable and inexpensive slot antennacover may be utilized to protect such slots 370. Slot antenna covers 106FIG. 8, are configured to cover slots 370 in waveguides 320 a, 320 b.Slot antenna covers 106 are adhered to the surrounding stainless steelof waveguides 320 a, 320 b using high temperature silicone rubber RoomTemperature Vulcanizing (“RTV”) sealant. This sealing approach createshigh temperature watertight seal between the cover and the surroundingmetal. Although an RTV sealant has been described in the exemplaryembodiment, other sealant means may be utilized to adhere antenna covers106 to waveguide 320 a, 320 b. The cover material must be compatiblewith high temperature operation, must be of low loss characteristicsrelative to microwave transmission, easily cleaned, durable, andinexpensive. For good microwave compatibility, materials with adielectric constant less than 6 and a loss tangent less that 0.2 havebeen found to provide such characteristics. Such materials must be thin,generally less than 0.015 inches thick, and be suitable for gluing using(RTV). A Teflon(PolyTetraFluoroEthylene (“PTFE”))/fiberglass fabricproduced by Saint Gobain (ChemFab Product Number 10 BT) which has oneside treated to accepted silicone rubber and is 0.01 inches thick isdescribed in the exemplary embodiment and has shown to have littleimpact on the microwave characteristics of the magnetron and microwavewaveguide system Results of Smith chart testing and water riseexperiments of the impedance of the waveguide and waveguide antenna forslot angles greater than 17 degrees(as measured from a horizontalcenterline, 379, FIG. 9) and without antenna cover 106 are approximatelythe same.

Although two microwave waveguides, 320 a, 320 b and two magnetrons, 100,are described per cooking zone, in other embodiments the waveguides maybe supplied by one larger magnetron, or alternatively various numbers ofmagnetrons may be utilized and the invention is not limited to twomagnetrons per cooking zone and applicant intends to encompass withinthe language any structure presently existing or developed in the futurethat performs the same function.

For optimum cooking, food product 310 is placed within oven zone 302upon conveyor transport means 399 a distance of at least 2.4 inches (foroptimal cooking uniformity) from front side wall 305 and back side wall306. The 2.45 inch measurement corresponds to one half a microwavewavelength or 2.4 inches (for optimal cooking uniformity) (E field null)for a 2.45 GHz microwave tube (microwave) frequency. This spacingpermits the E-field to expand and become more uniform prior to couplingwith the food product. Other side spacing placement may be utilized withother types of magnetrons systems.

The back side microwave waveguide is identical to the front side systemand microwave energy is broadcast from back waveguide 320 b to oven zone302 via slotted antenna 370 as previously described for the front side.Although waveguides 320 a and 320 b are configured in the same manner,infinite combinations of slot designs, slot configurations, slot widths,slot lengths, numbers of slots per waveguides and slot orientations arepossible per waveguide depending upon the type of oven desired. Themicrowave energy field therefore propagates through the oven zone in anevenly distributed pattern, coupling with the food product from alldirections, and providing an even electromagnetic energy distributionthroughout the oven zone without the need for a mechanical stirrer topropagate the electromagnetic field. Waveguides 320 a and 320 b arelocated on the front and back side walls of the oven, and therefore donot interfere with oven zone spent gas exhaust. Because microwavewaveguides are located on the side walls of the oven zone, they are notaffected by food spills, grease contamination, cleaning fluidcontamination or other contamination that normally affect a bottomlaunch microwave system. The microwave system of the present inventionwill therefore be less likely to be penetrated by grease, spills,cleaning materials and other contaminants because the systems are notlocated directly under the food product where hot contaminants willdrip. It is not required that side launch microwave waveguide beemployed and indeed microwave launching may be accomplished from anyoven cavity surface, with varying degrees of efficiencies.

Microwave waveguides 320 a, 320 b, FIG. 5 with slotted antenna 370 arepositioned along the front and back cavity walls such that cooking rack308 is slightly below slots 370. In this manner, microwave energy isdirected towards the top and bottom of the food product. For safety,microwave energy must be contained within cooking tunnel 394 andhistorically conveyor ovens incorporated long entrance and exit tunnelsto attenuate the microwave leakage escaping from the open oven tunnelends. These long tunnels not only require much additional floor space,but they result in oven cavity heights of only a few inches therebygreatly limiting the food products that can pass through such a conveyoroven. Our invention eliminates the need for long entrance and exittunnels and short cooking cavity height by employing the indexingconveyor approach coupled with tunnel doors, 397, 398 FIG. 1, asdiscussed herein.

Exemplary food product flow is illustrated in FIG. 4. In order to reducecontroller 334 complexity, the conveyor transport speed may be operatedat a fixed rate. This approach establishes dwell times wherein foodproduct 310 remains in a given cook zone for a fixed period of time. Inaddition to simplifying food recipe development and cooking recipealgorithms, a fixed dwell time also reduces complexities associated withconveyor drive mechanisms; resulting in a less expensive and morereliable conveyor transport means.

Food product 310 is placed upon conveyor transport means 399 and cooksettings for product 310 may be inputted automatically or manually, aspreviously described, into controller 334. Conveyor indexing motionbegins with the opening of ingress tunnel door 398, FIG. 1 and egresstunnel door 397. After doors 397, 398 open, conveyor transport means 399moves in a direction toward the cooking zones, (or zone) a distance suchthat food product 310 indexes, or moves forward to the first cook zone380, FIG. 4 within oven tunnel 394. Once conveyor transport means 399stops, doors 398 and 397 close around conveyor belt 399 as shown in FIG.7, and initiation of the cooking cycle may begin. After conveyor means399 comes to its initial stop, a second food product may be placed onconveyor transport means 399 at loading position 396, FIG. 4. In thoseinstances wherein microwave energy is used, a microwave seal must beachieved between conveyor belt 399 and doors 397, 398. Interface wall387, FIG. 7 is attached to belt 399 and doors 397, 398 close aroundinterface wall 387. The wall spacing on conveyor belt 399 corresponds tothe pitch length (oven zone centerline to oven zone centerline). Thespace between the partitions or walls also defines the landing zone forproduct loading area 396, FIG. 4. In addition to obtaining a seal forcontainment of microwave energy, closed doors 397, 398 reduce heatlosses associated with open cooking tunnel ends where hot gas leaves theopen tunnel ends with cool ambient gas rushing in to replace the losthot gas.

The door and wall microwave interface configuration between movabledoors 397, 398 and short wall 387, FIG. 7, on conveyor belt 399 is suchthat neither precise belt motion control (stopping at an exact location)or metal to metal contact between door edge 399 and the wall 387 isrequired. The wall and belt design is axially compliant. A one quarterwavelength choke 386, FIG. 7, is integrated into the bottom edge ofdoors 397, 398. Allowing for small displacement of the wall when thedoor closes is accomplished by the combination of the inverted “V” shapewhich guides door 398,397 together with short wall 387 by a compliant(not rigid) connection of wall 398 to belt 399. The inverted “V” shapehas sufficient length to support a one quarter wavelength choke(approximately 1.2 inches). The indexing motion of speed cookingconveyor appliance 301 results in microwave containment within thecooking tunnel because the conveyor is stationary during the cookingprocess.

With product 310 now in cook zone 380, controller 334 begins the cookingrecipe for food product 310. Cooking of food product 310 maybe completedwithin cook zone 380 or may be cooked in zones 381 and 382, FIG. 3, andit is not required that food product 310 utilize all three cook zonesfor completed cooking. Indeed, some cook zones may be used to defrostfrozen food product prior to cooking, or partial defrost followed bycooking. Dwell, or cooking time within each zone as previously describedmay be altered. The exemplary embodiment utilizes a 50 second conveyordwell setting per cooking zone. Food product 310 entering cook zone 380may therefore have a cooking recipe of 50 seconds comprised of 25seconds wherein 100% microwave energy and 100% gas flow is applied;followed by 25 seconds in which 50% microwave energy and 100% gas flowis applied.

At the completion of the first 50 second dwell period, controller 334begins the next indexing motion by opening tunnel doors 398, 397, FIG. 1and conveyor transport means 399 moves, or indexes one pitch lengthforward, moving product 310 from first cook zone 380 to second cook zone381, FIG. 4. In the event a second food product has been placed uponconveyor transport means 399 at loading position 396, FIG. 4, the secondfood product will move, or index into cook zone 380. The second foodproduct's cooking setting may now be entered into controller 334 in theevent the operator had not previously entered the cooking program, orthe program had not been automatically loaded as previously described.Once conveyor transport means 399 stops, tunnel doors 398, 397 againclose and controller 334 executes the cooking settings for the firstfood product in cook zone 381 and for the second food product in cookzone 380. Each food product is then cooked with its own cooking recipe.For example, the first food product in cooking zone 381 may require 100%gas flow and no microwave energy for the 50 second dwell period, whilethe second food product in cooking zone 380 may have 3 events programmedfor the 50 second dwell (e.g., 15 seconds of 100% gas flow with nomicrowave followed by 20 seconds of 100% microwave energy and no gasflow, followed by a final 15 seconds of 50% microwave and 50% gas flow).The number of events per cooking zone may be programmed in infinitecombinations and applicant does not limit the endless possiblecombinations of cooking recipes by the exemplary embodiment.

At the completion of the second 50 second dwell period doors 398, 397again open and the next conveyor transport means indexing motion isinitiated. Assuming a third food product has been placed upon conveyortransport means 399 in holding area 396, third food product 310 willindex forward to cooking zone 380, while the second food product willindex forward to cooking zone 381 and the first food product will indexforward to cooking zone 382. With the third food product now in cooking380, each food product can now be cooked with its own cooking recipesetting in the manner as previously described. With the completion ofthe third dwell period, doors 397, 398 again open and conveyor transportmeans 399 indexes forward one dwell length and first food product 310 isnow outside oven tunnel chamber 394 and resting upon transport means399, ready for unloading by the operator.

As previously described, speed cooking conveyor 301 consists of one ormore discrete cooking zones. The simplest one zone design will processonly one product at a time. A multi-zone design of ‘n’ zones would haveup to ‘n’ products in conveyor oven tunnel at a given time. The totalcapacity or speed cooking conveyor throughput (products per hour) is afunction of the number of cooking zones and the total cook time for aproduct. For example, a one zone speed cooking conveyor with a 150second dwell time will process approximately 24 products per hour. Athree zone oven with 50 second dwell time zones and a total cook time oftwo and one half minutes (3×50 seconds) will process approximately 72products per hour. A six zone speed cooking conveyor with 25 seconddwell times will process approximately 144 products per hour.

Because the food product is stationary in each cooking zone, the energyflows imparted to each food product may be controlled. Control of energyto the food product in a cooking zone includes the means to modulateboth the microwaves, when used, and gas flow energies that may beintroduced into the food product. A stationary food product duringcooking also permits the uniform application of the cooking energies(microwave, convective and optional radiant). Each cooking zone 380,381, 382 has open ends with a conveyor belt placed above and parallel tocook zone floor 304. The cook zones are placed end to end with theconveyor transport means passing through each cook zone and the zonesare separate by a distance in order to minimize the influence of gasflows or microwave energies coupling between cook zones. The distancesbetween cook zones will be determined by the particular conveyor oventhat is desired, and the amount of interference between cook zones thatmay be considered acceptable.

Although the exemplary embodiment illustrates the use of a two blowerdesign with one blower providing the gas flow to the front of each cookzone and a second blower for gas flow to the back of each cook zone,only one flow means, such as a blower may be utilized, or more than twogas flow means may be utilized and applicant intends to encompass withinthe language any structure presently existing or developed in the futurethat performs the same function.

Equipment bays for housing microwave circuit components, magnetrons,cooling fans, electronics, line filters, and other electrical componentsmay be located on the front side of appliance 301.

For a three cooking zone speed cooking conveyor oven, approximately 300cubic feet/minute (“cfm”) is utilized per cooking zone, although morethan 300 cfm and less than 300 cfm of gas per cooking zone may beutilized. This produces a hot gas flow supply loop, FIG. 5, wherein thecook zones are supplied with hot gas flow once cooking zone valves 388a, 388 b are opened. Actuation of the valves may be accomplished usingsolenoids or stepper motors 310 a, 310 b, FIG. 5, or any other meansknown to accomplish the function of opening and closing of valves 388 a,388 b. This method permits the blowers to operate at fixed speeds, andguarantees that sufficient flow is always present for safe reliableoperation of the gas heating source and grease clean-up system.

As previously described, a single energy source, heating means 314, witha single heat source controller, is used to supply heat to the gasreturning to the blower 316 a, 316 b. This approach greatly simplifiesthe heating system as compared to distributing heat sources among thevarious cooking zones. High power electrical wiring or natural gas lineconnections may also be centralized. For a gas fueled heating means,only a single burner and ignition module are needed. The centralizedapproach results in both oven construction simplification and reducedmaintenance.

Gas heating power requirements per cook zone of the exemplary embodimentare between approximately 5 and 7 kW for an electric appliance and 24 to34 kBtu/h for a direct fired natural gas powered heater. An electricheater for the exemplary embodiment is sized between approximately 15and 21 kW, while the gas fired gas heater would have a 72 to 102 kBtu/hneed. For either power source, a standard temperature controller couldbe employed (i.e., maintaining the blower discharge temperature). Foreither a gas fueled or electric fueled appliance, as previouslydescribed, appliance 301 may be scaled to permit use of available powersupplies. Additionally, a common gas heating means is ideal for ease ofinstallation, service, and the ability to incinerate grease particlesthat come in contact with the very hot products of combustion. Ofcourse, the hot products of cooking by-product combustion are mixed withthe gas returning to the blowers, resulting in a modest gas temperatureincrease of between 20° F.(−6.67° F.) to 60° F. (15.56° C.) and a numberof combustor types are suitable for this application including a surfacetype burner.

Although the present invention has been described in considerable detailwith reference to certain preferred versions thereof, other versions arepossible. For example, various sizes of conveyor ovens, bothconventional and speed cooking may be made. In these cases larger orsmaller component parts may be utilized, and fewer or more componentsmay be employed. In the case where it is desirable to make a smallerconveyor oven, one gas flow acceleration means may be utilized insteadof two; one microwave system utilized instead of two; smaller or fewerthermal devices, whether electric resistance or gas fired may be used.In cases wherein it is desirable for a larger speed cooking oven, largergas flow systems and microwave systems may be added to accomplish alarger speed cooking conveyor oven.

To summarize, the present invention provides for conventional and speedcooking conveyor ovens utilizing hot gas flow, and hot gas flow coupledwith microwave energy in order to achieve conventional and speed cookingof food products. Conventional or speed cooking of food products five toten times faster than conventional cooking with food quality, taste andappearance levels equal to and higher than that attained by conventionalcooking. The speed cooking conveyor oven is operable on various powersupplies and is simple and economical to manufacture, use and maintain,and is directly scalable to larger or smaller embodiments. The conveyoroven may operate as a gas fired, electric resistance fired oven, amicrowave oven or a combination gas and microwave oven. Additionally,the invention may be practiced wherein no gas deflection means areutilized, such as in the exemplary embodiment, gas deflection means areutilized as in alternate embodiments described herein. In cases whereinit is desirable for a larger production conveyor oven, multipleconveyors may be used with additional gas flow system and microwavesystems

Other modifications and improvements thereon will become readilyapparent. Accordingly, the spirit and scope of the present invention isto be considered broadly and limited only by the appended claims, andnot by the foregoing specification. Any element in a claim that does notexplicitly state “means for” performing a specific function, or “stepfor” performing a specific function, is not to be interpreted as a“means” or “step” clause as specified in 35 U.S.C. §112, ¶6. Inparticular, the use of “step of” in the claims herein is not intended toinvoke the provisions of 35 U.S.C. §112.

1. A conveyor oven for cooking a food product, comprising: a cookingtunnel comprising: at least one cooking zone, each cooking zonecomprising: a housing defining a cooking chamber; a conduit means forcirculating gas to and from the cooking chamber; a flow means forcausing circulation of the gas; a means for heating the gas; a first gasdirecting means disposed above the food product; the first gas directingmeans being operably associated with the conduit means; and a second gasdirecting means disposed above the food product, the second gasdirecting means also being operably associated with the conduit means;wherein the first and second gas directing means are configured to causethe gas from the first gas directing means to collide with the gas fromthe second gas directing means upon or above the upper surface of thefood product; and a conveyor for conveying products through the cookingzone.
 2. A conveyor oven for cooking a food product, comprising: acooking tunnel, comprising: at least one cooking zone, each cooking zonecomprising: a housing defining a cooking chamber; a conduit means forcirculating gas to and from the cooking chamber; a flow means forcausing circulation of the gas; a means for heating the gas; a first gasdirecting means disposed below the food product; the first gas directingmeans being operably associated with the conduit means; and a second gasdirecting means disposed below the food product, the second gasdirecting means also being operably associated with the conduit means;wherein the first and second gas directing means are configured to causethe gas from the first gas directing means to collide with the gas fromthe second gas directing means upon or below the lower surface of thefood product; and a conveyor for conveying products through the cookingzone.
 3. The oven of claim 1 further comprising: a first lower gasdirecting means disposed below the food product; the first lower gasdirecting means being operably associated with the conduit means; and asecond lower gas directing means disposed below the food product, thesecond lower gas directing means also being operably associated with theconduit means; wherein the first and second lower gas directing meansare configured to cause the gas from the first lower gas directing meansto collide with the gas from the second lower gas directing means uponor below the bottom surface of the food product.
 4. The oven of claim 1wherein each cooking zone cooks the food product independently of theother cooking zones.
 5. The oven of claim 1 further comprising: acontrol means for controlling the gas flow.
 6. The oven of claim 1wherein the gas exits the cooking chamber via the top wall.
 7. The ovenof claim 1 further comprising: at least one odor filter.
 8. The oven ofclaim 1 further comprising: a damper means for adjusting the amount ofsaid gas delivered via said conduit means to said first, second, firstlower and second lower gas directing means.
 9. The oven of claim 1wherein the flow means is a blower motor.
 10. The oven of claim 9wherein the blower motor runs at variable speeds.
 11. The oven of claim1 wherein the thermal means is a electric resistance heater.
 12. Theoven of claim 1 wherein the control means is a toggle switch.
 13. Theoven of claim 12 wherein the toggle switch controls the flow means. 14.The oven of claim 5 wherein the control means is a rotary switch. 15.The oven of claim 14 wherein the rotary switch controls the flow means.16. The oven of claim 1 further comprising: an electromagnetic source.17. The oven of claim 16 wherein the control means controls theelectromagnetic source, the damper means, the flow means, the thermalmeans, or combinations thereof.
 18. The oven of claim 16 wherein thecontrol means is comprised of toggle switches to control theelectromagnetic source, the damper means, the flow means, the thermalmeans, or combinations thereof.
 19. The oven of claim 16 wherein thecontrol means is comprised of rotary switches to control theelectromagnetic source, the damper means, the flow means, the thermalmeans, or combinations thereof.
 20. The oven of claim 16 furthercomprising: a control panel for controlling the operation of theelectromagnetic source, the damper means, the flow means, the thermalmeans, or combinations thereof.
 21. An oven as defined in claim 1further comprising: an egress opening to allow the gas to exit thecooking chamber and a catalyst located within said egress opening. 22.The oven of claim 21 wherein said egress opening is located in a topwall of the cooking chamber.
 23. The oven of claim 21 wherein saidegress opening is located in a side wall of the cooking chamber.
 24. Theoven of claim 21 wherein said egress opening is located in a back wallof the cooking chamber.
 25. The oven of claim 21 wherein said egressopening is located in a bottom wall of a cooking chamber.
 26. The ovenof claim 1 wherein the first gas directing means and the second gasdirecting means are located within a top wall.
 27. The oven of claim 1wherein the first gas directing means and the second gas directing meansare located within the right and left side walls.
 28. The oven of claim1 wherein the first gas directing means and the second gas directingmeans are located at the intersection of side walls and a top wall. 29.The oven of claim 1 wherein the first gas directing means and the secondgas directing means are located within a back wall.
 30. The oven ofclaim 2 wherein the first lower gas directing means and the second lowergas directing means are located within a bottom wall.
 31. The oven ofclaim 2 wherein the first lower gas directing means and the second lowergas directing means are located within the right and left side walls.32. The oven of claim 2 wherein the first lower gas directing means andthe second lower gas directing means are located at the intersection ofthe side walls and a bottom wall.
 33. The oven of claim 2 wherein thefirst lower gas directing means and the second lower gas directing meansare located within a back wall.
 34. The oven of claim 1 wherein thethermal means is a heater powered by gaseous fuel.
 35. The oven of claim34 wherein the gaseous fuel is propane.
 36. The oven of claim 34 whereinthe gaseous fuel is natural gas.
 37. The oven of claim 1 wherein saidoven is a speed cooking oven.
 38. The oven of claim 1 wherein said ovenis a conventional cooking oven.
 39. The oven of claim 1 wherein saidoven is an accelerated cooking oven.
 40. The oven of claim 1 whereinsaid oven is a recycling oven.
 41. The oven of claim 1 furthercomprising: at least two additional gas directing means for direction onat least one further food product.
 42. The oven of claim 1 furthercomprising: an ingress door disposed at one end of the cooking tunnel;an egress door disposed at the other end of the cooking tunnel; aplurality of sealing means carried by the conveyor for providing a sealbetween the ingress door and the cooking tunnel and between the egressdoor and the cooking tunnel.
 43. The oven of claim 7 wherein the odorfilter is a catalytic odor filter.
 44. The oven of claim 1 having ableed gas flow system further comprising: a gas bleed chamber, and anodor filter within the gas bleed chamber.
 45. The oven of claim 44wherein the odor filter causes catalytic destruction of cookingby-products.
 46. The oven of claim 45 further comprising a pre-heater toheat the bleed gas flow prior to the gas entering the catalytic odorfilter.